GI Dynamics Release: St. Vincent’s Clinic and Macquarie University in Sydney Incorporate EndoBarrier® Therapy Into Type 2 Diabetes and Obesity Treatment Option

Lexington, Massachusetts, United States and Sydney, Australia – 24 September 2012 – GI Dynamics, Inc. (ASX: GID) today announced that doctors at St. Vincent’s Clinic and Macquarie University Hospital (MUH) in Sydney now offer EndoBarrier ® Therapy, a revolutionary, non-surgical, non-pharmaceutical alternative to help patients take control of their type 2 diabetes and lose weight at the same time. The St. Vincent’s Clinic is situated within the greater St. Vincent’s Health Care campus, which is comprised of St. Vincent’s Public and St. Vincent’s Private Hospitals, both leading centres of innovation and patient care. Spearheading this treatment is Reginald V. Lord, M.D., F.R.A.C.S., a leading gastrointestinal, bariatric and general surgeon.

“The level of expertise and innovation offered by Prof. Lord and his team in Sydney is substantial, and we are thrilled that they have chosen to provide EndoBarrier Therapy,” said Stuart A. Randle, president and CEO of GI Dynamics. “We are excited about the commercial progress of EndoBarrier Therapy in Australia, and the addition of St. Vincent’s and MUH is great news for patients.”

Prof. Lord added, “St. Vincent’s has always been at the forefront of scientific discovery, medical innovation and patient care, so we are pleased to be able to add this innovative procedure to our repertoire of obesity and diabetes solutions. We also offer EndoBarrier Therapy through the new Macquarie University Hospital, which is possibly the most technologically advanced hospital in Australia. Its location in Sydney’s North West means that we are able to provide this treatment for patients across the broader Sydney metropolitan area.”

Delivered endoscopically (through the mouth) during a brief, non-surgical procedure, the EndoBarrier device is a thin, flexible, tube-shaped liner that forms a physical barrier between food and a portion of the intestinal wall. Once in place, it begins working immediately and has been shown to lower HbA1c (blood glucose) levels, achieve weight loss of approximately 20 percent and improve other important metabolic functions including cholesterol, blood pressure and triglycerides within one year. 1,2 EndoBarrier Therapy affects certain gastrointestinal hormones involved in insulin sensitivity, glucose metabolism and satiety, and these changes allow for rapid and sustained improvement of type 2 diabetes and weight loss. 3

The Australian Diabetes Council estimates that more than 3.5 million, or one in four, Australian adults have either diabetes or pre-diabetes; and that type 2 diabetes costs the country approximately A$3 billion a year. Additionally, more than 17 million Australians are overweight or obese; and obesity has now overtaken smoking as the leading cause of premature death and illness in the country. 4

About EndoBarrier Therapy

EndoBarrier Therapy is a breakthrough treatment for type 2 diabetes and/or obesity that has been clinically demonstrated to lower HbA1c levels, achieve weight loss of approximately 20 percent, and improve important metabolic measures including cholesterol, blood pressure and triglycerides. 1,2

It has been studied in 13 clinical trials and has been used in more than 500 patients. The EndoBarrier device is a thin, flexible, tube-shaped liner that forms a physical barrier between food and a portion of the wall of the intestine. EndoBarrier Therapy affects certain gastrointestinal hormones involved in insulin sensitivity, glucose metabolism and satiety, and these changes allow for rapid and sustained improvement of type 2 diabetes and weight loss. 3

About St. Vincent’s Hospital

St Vincent’s Hospital is Australia’s second oldest Hospital with an international reputation for its clinical, teaching and research endeavours and centres of excellence in heart and lung transplantation, bone marrow transplantation, cardiology, cancer, acquired immune deficiency syndrome/HIV, respiratory medicine, mental health and drug and alcohol services.

St Vincent’s Private Hospital is regarded as a pioneer and leading private acute hospital in Australia, providing a wide range of general and specialist medical and surgical services as well as a young adult mental health service. The Hospital has particular expertise in areas including cardiac care, cancer, neurosurgery, orthopaedics, head, neck and reconstructive surgery, urology laser, laparoscopic and robotic surgery. A teaching hospital of UNSW, Notre Dame, University of Tasmania and Australian Catholic University, St Vincent’s Private Hospital is co-located with both St Vincent’s Clinic and St Vincent’s Public Hospital.

About Macquarie University Hospital

Macquarie University Hospital (MUH) is Australia’s first and only private hospital on a university campus. Located in Sydney, Australia, MUH is a 183-bed, state-of-the-art facility offering a comprehensive range of services and specialist areas. With links to the Macquarie University Clinic and the Australian School of Advanced Medicine, the hospital is part of a large and integrated medical community that features the latest technology, much of it unavailable anywhere else in the country. Since opening in 2010, it has quickly become a renowned academic hospital, where doctors are committed to a culture of continuous improvement in patient care through teaching research. www.muh.org.au

About GI Dynamics

GI Dynamics, Inc. (ASX: GID) is pioneering the development and commercialization of effective, non-surgical treatments targeting the large and growing global patient populations with type 2 diabetes and obesity. The company’s flagship product, EndoBarrier®, is a novel, non-surgical device proven to lower blood glucose levels and promote weight loss in diabetic and obese patients during the implant period. GI Dynamics currently markets the EndoBarrier in select regions in Europe, South America and Australia, and is planning near-term commercial expansion into additional markets. The EndoBarrier is not approved for sale in the United States and is considered investigational. Founded in 2003, GI Dynamics is headquartered in Lexington, Massachusetts. For more information, please visit www.gidynamics.com.

1 Moura, GHD, et al, One Year Results of an Endoscopic, Duodenal-Jejunal Exclusion Device for Weight Loss and Control of Type 2 Diabetes. Hospital das Clinicas, University of São Paulo, São Paulo, Brazil. DT&T, February 2012, vol 14, no.2:183-189.

2 Escalona, A., et al, “Post-explant follow-up after 12 months implantation of an endoscopic duodenal-jejunal bypass liner.” Department of Digestive Surgery.” Faculty of Medicine Pontificia Universidad Católica de Chile. Annals of Surgery, June 2012 ,Vol 255, Issue 6, p 1080–1085.

3 C de Jonge, JW Greve, N Bouvy, et al, EndoBarrier Gastrointestinal Liner treatment rapidly improves diabetes parameters paralleled by increased postprandial GLP-1 and PYY levels in obese type 2 diabetic patients, Department of Surgery, Maastricht University Medical Centre, presented at IFSO 2011, Hamburg, Germany.

4 Obesity in Australia, Monash Obesity and Diabetes Institute, 2011.

Forward-Looking Statements

This announcement contains or may contain forward-looking statements that are based on management’s beliefs, assumptions and expectations and on information currently available to management. All statements that address operating performance, events or developments that we expect or anticipate will occur in the future are forward-looking statements, including without limitation our expectations with respect to our ability to commercialize our EndoBarrier® including our estimates of potential revenues, costs, profitability and financial performance; our ability to develop and commercialize new products including our ability to obtain reimbursement for our products; our expectations with respect to our clinical trials, including enrolment in or completion of our clinical trials and our associated regulatory submissions and approvals; our expectations with respect to the integrity or capabilities of our intellectual property position. Management believes that these forward-looking statements are reasonable as and when made. You should not place undue reliance on forward-looking statements because they speak only as of the date when made. GI Dynamics does not assume any obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. GI Dynamics may not actually achieve the plans, projections or expectations disclosed in forward-looking statements, and actual results, developments or events could differ materially from those disclosed in the forward- looking statements. Forward-looking statements are subject to a number of risks and uncertainties, described in “Risk Factors” in our Prospectus lodged with the Australian Securities & Investments Commission on 3 August 2011.

United States

Robert Crane, Chief Financial Officer

+1 (781) 357-3250

North America/Europe:

Susan Heins, Pure Communications Inc.

+ 1 (864) 286-9597

Australia

Kim Jacobs, Inteq Limited

+61 2 9231 3322

Australia:

Rebecca Wilson, Buchan Consulting Group

+61 3 9866 4722

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